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Preliminary Design of Pinhole camera for NSLS-II Project.

Description: The NSLS-II Light Source being built at Brookhaven National Laboratory is expected to provide very small emittances and electron beam sizes. High resolution imaging systems are required in order to provide robust measurements. The pinhole camera will utilize 6-fold magnification with a pinhole placed inside a crotch absorber. The pinhole is protected from high power synchrotron radiation with a filter made of refractory metal. In this paper we provide resolution analyses, heat load calculations, and optimization details for the NSLS-II pinhole camera, including beamline design.
Date: May 4, 2009
Creator: Pinayev,I.; Kosciuk, B. & Singh, O.
Partner: UNT Libraries Government Documents Department

DESIGN OF VISIBLE DIAGNOSTIC BEAMLINE FOR NSLS2 STORAGE RING

Description: A visible synchrotron light monitor (SLM) beam line has been designed at the NSLS2 storage ring, using the bending magnet radiation. A retractable thin absorber will be placed in front of the first mirror to block the central x-rays. The first mirror will reflect the visible light through a vacuum window. The light is guided by three 6-inch diameter mirrors into the experiment hutch. In this paper, we will describe design work on various optical components in the beamline. The ultra high brightness NSLS-II storage ring is under construction at Brookhaven National Laboratory. It will have 3GeV, 500mA electron beam circulating in the 792m ring, with very low emittance (0.9nm.rad horizontal and 8pm.rad vertical). The ring is composed of 30 DBA cells with 15 fold symmetry. Three damping wigglers will be installed in long straight sections 8, 18 and 28 to lower the emittance. While electrons pass through the bending magnet, synchrotron radiation will be generated covering a wide spectrum. There are other insertion devices in the storage ring which will generate shorter wavelength radiation as well. Synchrotron radiation has been widely used as diagnostic tool to measure the transverse and longitudinal profile. Three synchrotron light beam lines dedicated for diagnostics are under design and construction for the NSLS-II storage ring: two x-ray beam lines (pinhole and CRL) with the source points from Cell 22 BM{_}A (first bending in the DBA cell) and Cell22 three-pole wiggler; the third beam line is using visible part of radiation from Cell 30 BM{_}B (second bending magnet from the cell). Our paper focuses on the design of the visible beam line - SLM.
Date: March 28, 2011
Creator: Cheng, W.; Fernandes, H.; Hseuh, H.; Kosciuk, B.; Krinsky, S. & Singh, O.
Partner: UNT Libraries Government Documents Department

BPM Button Optimization to Minimize Distortion Due to Trapped Mode Heating

Description: The outer circumference of a BPM button and the inner circumference of the button housing comprise a transmission line. This transmission line typically presents an impedance of a few tens of ohms to the beam, and couples very weakly to the 50 ohm coaxial transmission line that comprises the signal path out of the button. The modes which are consequently excited and trapped often have quality factors of several hundred, permitting resonant excitation by the beam. The thermal distortion resulting from trapped mode heating is potentially problematic for achieving the high precision beam position measurements needed to provide the sub-micron beam position stability required by light source users. We present a button design that has been optimized via material selection and component geometry to minimize both the trapped mode heating and the resulting thermal distortion.
Date: May 4, 2009
Creator: Cameron,P.; Blednyk, A.; Kosciuk, B.; Pinayev, I.; Ravindranath, I. & Singh, O
Partner: UNT Libraries Government Documents Department

NSLS-II BPM System Protection from Rogue Mode Coupling

Description: Rogue mode RF shielding has been successfully designed and implemented into the production multipole vacuum chambers. In order to avoid systematic errors in the NSLS-II BPM system we introduced frequency shift of HOM's by using RF metal shielding located in the antechamber slot of each multipole vacuum chamber. To satisfy the pumping requirement the face of the shielding has been perforated with roughly 50 percent transparency. It stays clear of synchrotron radiation in each chamber.
Date: March 28, 2011
Creator: Blednykh, A.; Bach, B.; Borrelli, A.; Ferreira, M.; Hseuh, H.-C.; Hetzel, C. et al.
Partner: UNT Libraries Government Documents Department

NSLS-II INJECTION STRAIGHT DIAGNOSTICS

Description: The ultra-bright light source being developed by the NSLS-II project will utilize top-up injection and fine tuning of the injection process is mandatory. In this paper we present the diagnostics installed in the injection straight. Its use for commissioning and tuning of the injection cycle is also described. The NSLS-II storage ring will utilize a 9.3 meter long injection straight section shown in Fig. 1. Injection will be preformed with two septa (one pulsed, one DC) and four kickers. The stored beam will be shifted towards the pulsed septum up to IS mm and the nominal distance between centers of the injected and the bumped beam is 9.5mm. The NSLS-II beam position monitors will have turn-by-turn and first-turn capabilities and will be used for the commissioning and tuning the injection process. However, there are three additional BPMs and two beam intercepting OTR screens (flags) installed in the injection straight.
Date: March 28, 2011
Creator: Pinayev, I.; Blednykh, A.; Ferreira, M.; Fliller, R.; Kosciuk, B.; Shaftan, T.V. et al.
Partner: UNT Libraries Government Documents Department

Rogue Mode Shileding in NSLS-II Multipole Vacuum Chambers

Description: Modes with transverse electric field (TE-modes) in the NSLS-II multipole vacuum chamber can be generated at frequencies above 450MHz due to its geometric dimensions. Since the NSLS-II BPM system monitors signals within 10 MHz band at RF frequency of 500 MHz, frequencies of higher-order modes (HOM) can be generated within the transmission band of the band pass filter. In order to avoid systematic errors in the NSLS-II BPM system, we introduced frequency shift of HOMs by using RF metal shielding located in the antechamber slot. We demonstrated numerical modeling and experimental studies of the spurious TE modes in the NSLS-II vacuum chambers with antechamber slot. Calculated frequencies of TE-modes in considered chambers with and without RF shielding were verified experimentally. Flexible BeCu RF shielding inside each chamber at proper location shifts frequencies of H{sub 10p}-modes above {approx}900MHz, except chambers S6 odd and even. These chambers need special attention because of synchrotron radiation from downstream magnets. S6 odd multipole vacuum chamber needs to be measured and the RF shielding length has to be optimized. RF shielding looks adequate for baseline design. Fifty percent of open space provides adequate pumping speed.
Date: March 28, 2011
Creator: Ferreira, M.; Blednykh, A.; Bacha, B.; Borrelli, A.; Hseuh, H.-C.; Kosciuk, B. et al.
Partner: UNT Libraries Government Documents Department

Development of High Stability Supports for NSLS-II RF BPMS

Description: The NSLS-II Light Source being built at Brookhaven National Laboratory is expected to provide submicron stability of the electron orbit in the storage ring in order to fully utilize the very small emittances of the electron beam. This requires high stability supports for BPM pickup electrodes located near insertion device sources. Here we provide details for the design and development of these supports as well as measurement of thermal and vibrational stability of a prototype support.
Date: May 4, 2009
Creator: Kosciuk,B.; Alforque, R.; Bacha, B.; Cameron, P.; Lincoln, F.; Ravindranath, V. et al.
Partner: UNT Libraries Government Documents Department

PERFORMANCE OF THE DIAGNOSTICS FOR NSLS-II LINAC COMMISSIONING

Description: The National Synchrotron Light Source II (NSLS-II) is a state of the art 3-GeV third generation light source currently under construction at Brookhaven National Laboratory. The NSLS-II injection system consists of a 200 MeV linac, a 3-GeV booster synchrotron and associated transfer lines. The transfer lines not only provide a means to deliver the beam from one machine to another, they also provide a suite of diagnostics and utilities to measure the properties of the beam to be delivered. In this paper we discuss the suite of diagnostics that will be used to commission the NSLS-II linac and measure the beam properties. The linac to booster transfer line can measure the linac emittance with a three screens measurement or a quadrupole scan. Energy and energy spread are measured in a dispersive section. Total charge and charge uniformity are measured with wall current monitors in the linac and transformers in the transfer line. We show that the performance of the diagnostics in the transfer line will be sufficient to ensure the linac meets its specifications and provides a means of trouble shooting and studying the linac in future operation.
Date: March 28, 2011
Creator: Fliller III, R.; Padrazo, D.; Wang, G.M.; Heese, R.; H.-C., Hseuh; Johanson, M. et al.
Partner: UNT Libraries Government Documents Department

NSLS-II RF BEAM POSITION MONITOR

Description: An internal R&D program has been undertaken at BNL to develop a sub-micron RF Beam Position Monitor (BPM) for the NSLS-II 3rd generation light source that is currently under construction. The BPM R&D program started in August 2009. Successful beam tests were conducted 15 months from the start of the program. The NSLS-II RF BPM has been designed to meet all requirements for the NSLS-II Injection system and Storage Ring. Housing of the RF BPM's in +-0.1 C thermally controlled racks provide sub-micron stabilization without active correction. An active pilot-tone has been incorporated to aid long-term (8hr min) stabilization to 200nm RMS. The development of a sub-micron BPM for the NSLS-II has successfully demonstrated performance and stability. Pilot Tone calibration combiner and RF synthesizer has been implemented and algorithm development is underway. The program is currently on schedule to start production development of 60 Injection BPM's starting in the Fall of 2011. The production of {approx}250 Storage Ring BPM's will overlap the Injection schedule.
Date: March 28, 2011
Creator: Vetter, K.; Della Penna, A. J.; DeLong, J.; Kosciuk, B.; Mead, J.; Pinayev, I. et al.
Partner: UNT Libraries Government Documents Department

DESIGN AND PRELIMINARY TEST OF THE 1500 MHZ NSLS-II PASSIVE SUPERCONDUCTING RF CAVITY

Description: NSLS-II is a new ultra-bright 3 GeV 3rd generation synchrotron radiation light source. The performance goals require operation with a beam current of 500mA and a bunch current of at least 0.5mA. Ion clearing gaps are required to suppress ion effects on the beam. The natural bunch length of 3mm is planned to be lengthened by means of a third harmonic cavity in order to increase the Touschek limited lifetime. Earlier work described the design alternatives and the geometry selected for a copper prototype. We subsequently have iterated the design to lower the R/Q of the cavity and to increase the diameter of the beam pipe ferrite HOM dampers to reduce the wakefield heating. A niobium cavity and full cryomodule including LN2 shield, magnetic shield and insulating vacuum vessel have been fabricated and installed. A passive SRF 3rd harmonic cavity consisting of two tightly coupled cells has been designed and fabricated for NSLS-II. Initial cold tests of this cavity are very promising. These tests have verified that the cavity frequency and mode separation between the 0 and {pi}-modes can be set at manufacture. Further, the frequency separation can be maintained over wide tuning ranges necessary for operation. Future work includes HOM damper and motorized tuner development.
Date: March 28, 2011
Creator: Rose, J.; Gash, W.; Kosciuk, B.; Ravindranath, V.; Sikora, B.; Sharma, S. et al.
Partner: UNT Libraries Government Documents Department

NSLS-II Transport Line Progress

Description: The National Synchrotron Light Source II (NSLS-II) is a state-of-the-art 3-GeV third generation light source currently under construction at Brookhaven National Laboratory. The NSLS-II injection system consists of a 200 MeV linac, a 3-GeV booster synchrotron and associated transfer lines. The first part of the Linac to Booster Transport (LBT) line has been installed for linac commissioning. This part includes all components necessary to commission the NSLS-II linac. The second part of this transport line is undergoing installation. Initial results of hardware commissioning will be discussed. The Booster to Storage Ring (BSR) transport line underwent a design review. The first part of the BSR transport line, consisting of all components necessary to commission the booster will be installed in 2012 for booster commissioning. We report on the final design of the BSR line along with the plan to commission the booster.
Date: May 20, 2012
Creator: P., Fliller R.; Wahl, W.; Anderson, A.; Benish, B.; DeBoer, W.; Ganetis, G. et al.
Partner: UNT Libraries Government Documents Department

PROGRESS WITH NSLS-II INJECTION STRAIGHT SECTION DESIGN

Description: The NSLS-II injection straight section (SR) consists of pulsed and DC bumps, septa system, beam trajectory correction and diagnostics systems. In this paper we discuss overall injection straight layout, preliminary element designs, specifications for the pulsed and DC magnets and their power supplies, vacuum devices and chambers and diagnostics devices. Prior to selecting the current 'conventional' design of the injection straight section we analyzed an option of injection via pulsed multipole pioneered at PF-AR. We found that this promising approach was not suited to the NSLS-II storage ring optics, since it would require a impractically compact arrangement of the injection straight section components and a complex modification of the transport line optics due to the strong focusing of the injected beam passing off the pulsed multipole axis. In addition, the requirement for a small injection transient of the stored beam orbit severely constrains the vertical alignment tolerance of the pulsed multipole. The design of the NSLS-II injection straight section is now completed with exception of transition chamber details, which will be adjusted to accommodate the actual layouts of the pulsed magnets.
Date: March 28, 2011
Creator: Shaftan, T.; Blednykh, A.; Casey, B.; Dalesio, B.; Faussete, R.; Ferreira, M. et al.
Partner: UNT Libraries Government Documents Department

NSLS-II Beam Diagnostics Overview

Description: A new 3rd generation light source (NSLS-II) is in the early stages of construction at Brookhaven National Laboratory. The NSLS-II facility will provide ultra high brightness and flux with exceptional beam stability. It presents several challenges for diagnostics and instrumentation, related to the extremely small emittance. In this paper, we present an overview of all planned instrumentation systems, results from research and development activities; and then focus on other challenging aspects.
Date: May 4, 2009
Creator: Singh,O.; Alforque, R.; Bacha, B.; Blednykh, A.; Cameron, P.; Cheng, W. et al.
Partner: UNT Libraries Government Documents Department